The obesity epidemic in the US includes not only adults but extends to the preschool-age group. Although genetics plays a role in the development of obesity, only environmental and behavioral changes can account for the recent increases. Thus, to reverse the current trend of increasing prevalence of obesity and its attendant comorbidities, population-based interventions, focusing on behavioral changes are required. Because lifestyle behaviors have their origins in childhood and the increased prevalence of obesity is present by age 5, interventions to alter the natural course of obesity need to begin during the preschool years. We propose a novel, innovative, exciting, day care-based approach to prevent the development of childhood obesity. Brocodile the Crocodile, recognizes the increasing role that day care plays in the lives of young children and is designed to be fun and appealing to young children, their parents, and their day care providers. This three- component program consists of: l) developmentally-appropriate Music Movement, based on a well-developed music-movement program, Kindermusik(R), capitalizes on children's gross motor abilities, response to repetition, and enjoyment of music; 2) Healthy Eating, a developmentally-based heart-healthy eating program, focusing on behavior and environment; and 3) Parenting, a skills-based program. We propose to conduct a 18-month, randomized clinical trial among 20 day care centers, where 10 Intervention centers will receive the Brocodile the Crocodile program and 10 centers will be the Controls, and to evaluate, as the primary outcome, the difference in the change in BMI (adiposity) between the children attending the Intervention vs. Control day care centers. In addition, the relationship of other variables (e.g., child diet, physical activity, TV viewing, parent behavior, etc.), to change in BMI will be evaluated, as will screening strategies to identify children at greatest risk of developing obesity. At the conclusion of this research project, an innovative day care-based obesity prevention program will have been developed, implemented, and evaluated for effectiveness in preventing childhood obesity. The findings will help fill the knowledge gap and guide future recommendations for the prevention of obesity in young children.